Battery charging and discharging device and new energy automobile

Abstract

The embodiment of the utility model provides a battery charging and discharging device and a new energy automobile. The battery charging and discharging device comprises a charging interface, an electric drive assembly and a battery pack interface, the charging interface is used for accessing an external direct-current power supply and comprises a positive electrode access end and a negative electrode access end; the electric drive assembly comprises a motor, a first bridge arm and a second bridge arm; each phase line of the motor is respectively connected with the first end of the first bridge arm and the first end of the second bridge arm; the second end of the first bridge arm is connected with the anode access end; the second end of the second bridge arm is connected with the negative electrode access end; in the battery pack interface, a first access end used for accessing a positive electrode of a power battery pack is connected with a second end of the first bridge arm, a second access end used for accessing a negative electrode of the power battery pack is connected with a second end of the second bridge arm, and one of the first access end and the second access end is connected with the motor. The purpose of increasing the charging speed at least can be achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of new energy vehicles, and particularly relates to a battery charging and discharging device and a new energy vehicle. BACKGROUND

[0002] New energy vehicles are transportation tools that have rapidly developed in recent years and are widely concerned for their environmental protection and energy saving features. New energy vehicles mainly include pure electric vehicles and plug-in hybrid electric vehicles, and all use electric power as the main power source, and have lower emissions and higher energy efficiency than traditional fuel vehicles.

[0003] However, in the process of popularization of new energy vehicles, charging problems gradually become prominent. For example, due to the current limit of some charging piles, the charging current of batteries with fast charging capability is also limited, which causes the charging power of the batteries to be unable to be improved, and further affects the charging speed of the batteries, and the fast charging demand of the batteries cannot be met. SUMMARY

[0004] Therefore, in order to at least solve the technical problem that the charging speed of the battery is low due to the influence of the output current of the charging pile on the charging current of the battery in the related art, the purpose of the utility model is to provide a battery charging and discharging device and a new energy vehicle.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the embodiments of the utility model is as follows:

[0006] The first aspect of the embodiments of the utility model provides a battery charging and discharging device, which comprises:

[0007] A charging interface is used for connecting an external direct-current power supply and comprises a positive connection end and a negative connection end;

[0008] An electric drive assembly comprises a motor, a first bridge arm and a second bridge arm. Each phase line of the motor is connected with the first end of the first bridge arm and the first end of the second bridge arm. The second end of the first bridge arm is connected with the positive connection end. The second end of the second bridge arm is connected with the negative connection end.

[0009] A battery pack interface is used for connecting a first connection end of a positive electrode of a power battery pack with the second end of the first bridge arm, and a second connection end of a negative electrode of the power battery pack with the second end of the second bridge arm. One of the first connection end and the second connection end is connected with the motor.

[0010] In the case that the output voltage of the external direct-current power supply is higher than the charging voltage of the power battery pack, and the output current of the external direct-current power supply is smaller than the maximum charging current of the power battery pack, the first bridge arm and the second bridge arm are alternately turned on and off to alternately switch a step-down charging circuit and a current-increasing charging circuit.

[0011] The step-down charging circuit is used for charging the inductance in the motor, and comprises the external DC power supply, the power battery pack, a bridge arm in the step-down charging circuit in a conducting state, and the inductance.

[0012] The step-up charging circuit is used for charging the power battery pack, and comprises the power battery pack, the first relay, a bridge arm in the step-up charging circuit in a conducting state, and the inductance.

[0013] In an optional embodiment, the second access end is connected with the motor.

[0014] In the step-down charging circuit, the first bridge arm is in a disconnected state, and the second bridge arm is in a conducting state.

[0015] In the step-up charging circuit, the first bridge arm is in a conducting state, and the second bridge arm is in a disconnected state.

[0016] In an optional embodiment, the first access end is connected with the motor.

[0017] In the step-down charging circuit, the first bridge arm is in a conducting state, and the second bridge arm is in a disconnected state.

[0018] In the step-up charging circuit, the first bridge arm is in a disconnected state, and the second bridge arm is in a conducting state. In an optional embodiment, the battery charging and discharging device further comprises:

[0019] a first relay, which is connected in series between the motor and one end of the battery pack interface connected with the motor;

[0020] and a second relay; the second relay is connected in parallel with a branch formed by the first relay and the electric drive assembly.

[0021] When the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack, and the output current of the external DC power supply is greater than or equal to the maximum charging current of the power battery pack, the first relay, the first bridge arm and the second bridge arm are all in a disconnected state, the second relay is in a conducting state, and the external DC power supply, the power battery pack and the second relay form a direct charging circuit.

[0022] When the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack, and the output current of the external DC power supply is less than the maximum charging current of the power battery pack, the second relay is in a disconnected state.

[0023] In an optional embodiment, the battery charging and discharging device further comprises a third relay; the third relay is connected in series between the battery pack interface and the electric drive assembly, and the third relay and the second relay are connected to different access ends of the battery pack interface.

[0024] In an optional embodiment, the battery charging and discharging device further comprises:

[0025] a first relay connected in series between the motor and one end of the battery pack interface connected to the motor;

[0026] a fourth relay connected to the motor at one end and to a target bridge arm at the other end, the target bridge arm being the first bridge arm or the second bridge arm;

[0027] and a fifth relay connected between the target bridge arm and the fourth relay;

[0028] In the case where the output voltage of the external DC power supply is lower than or equal to the charging voltage of the power battery pack, the first relay and the fifth relay are in an open state, the fourth relay is in a closed state, and the first bridge arm and the second bridge arm are alternately turned on and off to alternately switch the energy storage charging circuit and the step-up charging circuit.

[0029] The energy storage charging circuit is used for charging the inductor, and comprises the external DC power supply, the fourth relay, the inductor, and the bridge arm in the closed state in the energy storage charging circuit.

[0030] The step-up charging circuit is used for charging the power battery pack, and comprises the external DC power supply, the fourth relay, the inductor, the bridge arm in the closed state in the step-up charging circuit, and the power battery pack.

[0031] In an optional embodiment, the battery charging and discharging device further comprises a first voltage stabilizing capacitor; the first voltage stabilizing capacitor is connected in parallel to the battery pack interface.

[0032] In an optional embodiment, at least one of the two ends of the first voltage stabilizing capacitor is connected to the battery pack interface through a relay.

[0033] In an optional embodiment, a relay is connected in series between the battery pack interface and the first bridge arm; and / or

[0034] a relay is connected in series between the battery pack interface and the second bridge arm; and / or

[0035] a relay is connected in series between the first bridge arm and the positive access end; and / or

[0036] a relay connected in series between the second bridge arm and the negative access terminal; and / or

[0037] a main fuse connected in series between the battery pack interface and the first bridge arm; and / or

[0038] a shunt connected in series between the battery pack interface and the second bridge arm.

[0039] In an optional embodiment, the battery charging and discharging device further comprises:

[0040] a sixth relay connected at one end between a plurality of battery groups contained in the power battery pack and connected at the other end to the motor;

[0041] when the temperature of the power battery pack is less than a set temperature threshold, the first relay is in an open state, the sixth relay is in a closed state, the second relay and the third relay are alternately turned on and off, and the first bridge arm and the second bridge arm are alternately turned on and off to alternately switch the battery discharging circuit and the battery charging circuit, thereby achieving the temperature rise of the power battery pack;

[0042] in the battery discharging circuit, the third relay is closed, the second relay is open, part of the battery groups in the power battery pack are short-circuited by the sixth relay, and the battery groups in the power battery pack that are not short-circuited discharge to the inductor;

[0043] in the battery charging circuit, the second relay is closed, the third relay is open, part of the battery groups in the power battery pack are open-circuited, and the battery groups in the power battery pack that are not open-circuited are charged by the inductor.

[0044] In an optional embodiment, the charging interface is further used to access an external load.

[0045] In an optional embodiment, the battery charging and discharging device further comprises:

[0046] a power supply interface connected to the charging interface or the battery pack interface, used to introduce an external DC power supply through the charging interface or introduce a power supply provided by the power battery pack through the battery pack interface.

[0047] the power supply interface is connected to the charging interface or the battery pack interface, used to introduce an external DC power supply through the charging interface or introduce a power supply provided by the power battery pack through the battery pack interface.

[0048] the power supply interface is connected to the charging interface or the battery pack interface, used to introduce an external DC power supply through the charging interface or introduce a power supply provided by the power battery pack through the battery pack interface.

[0049] In an optional embodiment, the electric drive assembly further comprises a second voltage stabilizing capacitor, two ends of the second voltage stabilizing capacitor are connected to the second end of the first bridge arm and the second end of the second bridge arm, respectively.

[0050] In an optional embodiment, the battery charging and discharging device further comprises:

[0051] a pre-charging circuit comprising a resistor and a seventh relay connected in series with each other; the pre-charging circuit is connected in parallel with the relay connected to the first access end;

[0052] in a case where the difference between the terminal voltage of the second voltage stabilizing capacitor and the terminal voltage of the power battery pack is greater than or equal to a set voltage difference, the seventh relay is in a conducting state, and the relay connected in parallel with the pre-charging circuit is in a non-conducting state;

[0053] in a case where the difference between the terminal voltage of the second voltage stabilizing capacitor and the terminal voltage of the power battery pack is less than a set voltage difference, the seventh relay is in a non-conducting state, and the relay connected in parallel with the pre-charging circuit is in a conducting state.

[0054] In a second aspect of the embodiments of the utility model, a new energy automobile is provided, which comprises:

[0055] a power battery pack; and

[0056] a battery charging and discharging device; the battery charging and discharging device is the battery charging and discharging device provided in any one of the first aspect.

[0057] The battery charging and discharging device and the new energy automobile provided in any one of the above aspects of the embodiments of the utility model are configured with a step-down charging loop and a step-up charging loop through cooperation of the charging interface, the electric drive assembly and the battery pack interface, so that in a case where the output voltage of the external DC power source connected to the charging interface is higher than the charging voltage of the power battery pack connected to the battery pack interface and the output current of the external DC power source is less than the maximum charging current of the power battery pack, the inductance in the power battery pack and the electric drive assembly is first charged through the step-down charging loop, and then the inductance is charged for the power battery pack through the step-up charging loop. It can be seen that in the process of charging the power battery pack and the inductance through the step-down charging loop, the external DC power source can be stepped down, i.e. the output voltage of the external DC power source is distributed to the power battery pack and the inductance, so as to step down the voltage output by the external DC power source to the charging voltage of the power battery pack, and the current of the external DC power source is pulled to the maximum, i.e. the maximum output current of the external DC power source can be achieved. Therefore, in the process of charging the power battery pack through the step-up charging loop, the charging power of the external DC power source remains unchanged, so the overall charging power of the step-up charging loop also remains unchanged, and power is equal to the product of voltage and current, so the decrease of the charging voltage can increase the charging current, so as to achieve the purpose of improving the charging current of the power battery pack and improve the charging speed.

[0058] In addition, even if the output voltage and the output current of the external direct-current power supply have various parameters, it is known from the above that the battery charging and discharging device provided by the embodiment of the utility model can be used to realize the fast charging of the power battery pack as long as the output voltage is higher than the charging voltage of the power battery pack and the output current is less than the maximum charging current of the power battery pack, and therefore the battery charging and discharging device provided by the embodiment of the utility model can also be compatible with charging piles with different parameters in this case.

[0059] Furthermore, since the electric drive assembly can reuse the electric drive assembly of the new energy vehicle, the manufacturing cost of the battery charging and discharging device and the new energy vehicle can be reduced, and the space utilization in the vehicle can be improved.

[0060] In order to make the above-mentioned purpose, features and advantages of the utility model more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0061] In order to more clearly illustrate the technical scheme of the embodiment of the utility model, the following will briefly introduce the drawings needed to be used in the embodiment, and it should be understood that the following drawings only show some embodiments of the utility model, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0062] Figure 1 A structural block diagram of a battery charging and discharging device provided by the embodiment of the utility model is shown;

[0063] Figure 2a A circuit principle diagram of a battery charging and discharging device provided by the embodiment of the utility model is shown;

[0064] Figure 2b A circuit principle diagram of another battery charging and discharging device provided by the embodiment of the utility model is shown;

[0065] Figure 3a A circuit principle diagram of another battery charging and discharging device provided by the embodiment of the utility model is shown;

[0066] Figure 3b A circuit principle diagram of another battery charging and discharging device provided by the embodiment of the utility model is shown;

[0067] Figure 4a A circuit principle diagram of a battery charging and discharging device provided by the embodiment of the utility model is shown;

[0068] Figure 4b A circuit principle diagram of another battery charging and discharging device provided by the embodiment of the utility model is shown;

[0069] Figure 4c A circuit principle diagram of the battery charging and discharging device with the boosting charging function is shown;

[0070] Figure 4d A circuit principle diagram of the battery charging and discharging device with the boosting charging function is shown;

[0071] Figure 4e A circuit principle diagram of the battery charging and discharging device with the boosting charging function is shown;

[0072] Figure 4f A circuit principle diagram of the battery charging and discharging device with the boosting charging function is shown;

[0073] Figure 4g A circuit principle diagram of the battery charging and discharging device with the boosting charging function is shown;

[0074] Figure 4h A circuit principle diagram of the battery charging and discharging device with the boosting charging function is shown;

[0075] Figure 5a A circuit principle diagram of the battery charging and discharging device with the first voltage stabilizing capacitor is shown;

[0076] Figure 5b A circuit principle diagram of the battery charging and discharging device with the first voltage stabilizing capacitor is shown;

[0077] Figure 5c A circuit principle diagram of the battery charging and discharging device with the first voltage stabilizing capacitor is shown;

[0078] Figure 5d A circuit principle diagram of the battery charging and discharging device with the first voltage stabilizing capacitor is shown;

[0079] Figure 5e A circuit principle diagram of the battery charging and discharging device with the first voltage stabilizing capacitor is shown;

[0080] Figure 5f A circuit principle diagram of the battery charging and discharging device with the first voltage stabilizing capacitor is shown;

[0081] Figure 5gThe circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model is shown in the figure;

[0082] Figure 5h The circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model is shown in the figure;

[0083] Figure 5i The circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model is shown in the figure;

[0084] Figure 5j The circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model is shown in the figure;

[0085] Figure 5k The circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model is shown in the figure;

[0086] Figure 6a The circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model is shown in the figure;

[0087] Figure 6b The circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model is shown in the figure;

[0088] Figure 7a The circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model is shown in the figure;

[0089] Figure 7b The circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model is shown in the figure;

[0090] Figure 7c The circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model is shown in the figure;

[0091] Figure 7d The circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model is shown in the figure;

[0092] Figure 7e The circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model is shown in the figure;

[0093] Figure 8 The circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model is shown in the figure.

[0094] Icon: 100 - charging interface, 200 - electric drive assembly, 210 - first bridge arm, 220 - second bridge arm, M - motor, 300 - battery pack interface, K1 - first relay, K2 - second relay, K3 - third relay, K4 - fourth relay, K5 - fifth relay, K6 - sixth relay, K7 - seventh relay, K8 - eighth relay, K9 - relay, Ka - relay, Kb - relay, R - resistor, C1 - first voltage stabilizing capacitor, C2 - second voltage stabilizing capacitor, A - main fuse, B - shunt. DETAILED DESCRIPTION

[0095] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0096] Therefore, the detailed description of the embodiments of the present application provided in the drawings below is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0097] It should be noted that similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0098] In the description of the present application, it should be noted that if terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are mentioned, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the corresponding drawings, or the orientation or positional relationship when the product of the present application is normally placed, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third", etc. are only used for differentiation, and cannot be understood as indicating or implying relative importance.

[0099] In addition, the terms "horizontal", "vertical", etc. do not mean that the components must be absolutely horizontal or hanging, but can be slightly inclined, for example, "horizontal" can only mean that its direction is more inclined to horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0100] In the embodiments of the utility model, it is still to be explained that unless there is definite stipulation and limitation, the terms "arrange", "install", "connect", "connect" and the like should be understood in a broad sense, for example, it can be fixed connection, can also be detachable connection, or integral connection, can be mechanical connection, can also be electrical connection, can be directly connected, can also be connected through intermediate medium, and can also be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to specific circumstances.

[0101] To solve the technical problem that the battery charging speed is low due to the influence of the output current of the charging pile on the charging current of the battery in the related art, the utility model embodiment provides a battery charging and discharging device first, which is configured with a step-down charging loop and a step-up charging loop by cooperating with a charging interface, an electric drive assembly and a battery pack interface, so that the output voltage of the external DC power source connected to the charging interface is higher than the charging voltage of the power battery pack connected to the battery pack interface, and the output current of the external DC power source is less than the maximum charging current of the power battery pack, and the inductance in the power battery pack and the electric drive assembly is charged through the step-down charging loop first, and then the power battery pack is charged through the step-up charging loop. It can be seen that during the charging process of the power battery pack and the inductance by using the step-down charging loop, the step-down effect can be generated on the external DC power source, that is, the output voltage of the external DC power source is distributed to the power battery pack and the inductance, so as to realize the step-down of the voltage output by the external DC power source to the charging voltage of the power battery pack, and the current of the external DC power source is pulled to the maximum, that is, the maximum output current of the external DC power source can be achieved. Therefore, during the charging process of the power battery pack by using the step-up charging loop, the charging power of the step-up charging loop remains unchanged because the charging power of the external DC power source remains unchanged, and the power is equal to the product of voltage and current, so the decrease of the charging voltage can increase the charging current, thereby achieving the purpose of increasing the charging current of the power battery pack and improving the charging speed.

[0102] In addition, even if the output voltage and output current of the external DC power source have multiple parameters, as known from the above, as long as the output voltage is higher than the charging voltage of the power battery pack and the output current is less than the maximum charging current of the power battery pack, the battery charging and discharging device provided by the utility model embodiment can be used to realize fast charging of the power battery pack, so the battery charging and discharging device provided by the utility model embodiment can also be compatible with charging piles with different parameters in this case.

[0103] Hereinafter, the battery charging and discharging device provided by the utility model embodiment will be described in combination with Figure 1 The battery charging and discharging device provided by the utility model embodiment will be described, please refer to Figure 1 , Figure 1It is a structural block diagram of a battery charging and discharging device provided by the embodiment of the utility model; the battery charging and discharging device comprises a charging interface 100, an electric drive assembly 200 and a battery pack interface 300.

[0104] The charging interface 100 is used for accessing an external DC power supply and comprises a positive access end and a negative access end.

[0105] The electric drive assembly 200 comprises a motor M, a first bridge arm 210 and a second bridge arm 220; each phase line of the motor M is connected with the first end of the first bridge arm 210 and the first end of the second bridge arm 220 respectively; the second end of the first bridge arm 210 is connected with the positive access end; and the second end of the second bridge arm 220 is connected with the negative access end.

[0106] The battery pack interface 300 is used for connecting the first access end of the positive pole of a power battery pack with the second end of the first bridge arm 210 and connecting the second access end of the negative pole of the power battery pack with the second end of the second bridge arm 220, and one of the first access end and the second access end is connected with the motor.

[0107] In the case that the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack and the output current of the external DC power supply is smaller than the maximum charging current of the power battery pack, the first bridge arm 210 and the second bridge arm 220 are alternately turned on and off to alternately switch a step-down charging circuit and a current-increasing charging circuit.

[0108] The step-down charging circuit is used for charging the inductance in the motor M and the power battery pack, and comprises the external DC power supply, the power battery pack, the bridge arm in the on state in the step-down charging circuit and the inductance.

[0109] The current-increasing charging circuit is used for charging the power battery pack, and comprises the power battery pack, the bridge arm in the on state in the current-increasing charging circuit and the inductance.

[0110] The battery charging and discharging device provided by the embodiment of the utility model can be sold as a separate product, or can be part of a carrier using a battery as a power source, wherein the carrier can include but is not limited to a new energy vehicle, a new energy aircraft or other new energy vehicles.

[0111] Taking the new energy vehicle as an example, the battery charging and discharging device provided by the embodiment of the utility model reuses the electric drive assembly 200 of the new energy vehicle, without the need to additionally set other components to improve the charging speed of the external DC power supply, thereby reducing the manufacturing cost of the charging and discharging device and improving the space utilization rate in the vehicle.

[0112] The working principle of the battery charging and discharging device provided in the embodiments of the present application is described below by taking the application of the battery charging and discharging device provided in the embodiments of the present application to a new energy vehicle as an example.

[0113] When the battery charging and discharging device is applied to a new energy vehicle, the power battery pack can be connected to the battery pack interface 300. Thus, in the scenario where the power battery pack of the new energy vehicle needs to be charged, an external DC power source can be connected to the charging interface 100 of the battery charging and discharging device, for example, the charging interface 100 is connected to a charging pile. Subsequently, the controller in the new energy vehicle can learn the output voltage and output current of the external DC power source currently connected to the charging interface 100 by using a related technology, and compare the output voltage and output current with the charging voltage and maximum charging current of the power battery pack, respectively.

[0114] After comparison, if it is determined that the output voltage of the external DC power source is higher than the charging voltage of the power battery pack and the output current is less than the maximum charging current of the power battery pack, in order to ensure the charging speed of the power battery pack, the controller controls the first bridge arm 210 and the second bridge arm 220 to alternately turn on and off to alternately switch the step-down charging loop and the step-up charging loop. In some examples, the controller can control the first bridge arm 210 and the second bridge arm 220 to alternately turn on and off at a set frequency, wherein the set frequency can be obtained by experience or experiment, for example, it can be set to 100,000 times / s.

[0115] In addition, in the case where the first bridge arm and / or the second bridge arm includes a plurality of switch tubes, if the first bridge arm or the second bridge arm is turned on, the number of switch tubes turned on in the first bridge arm or the second bridge arm can be adjusted according to the current size in the loop, for example, in the case where the current in the loop is large, the number of switch tubes turned on can be increased to achieve the purpose of current sharing, avoid the current through the switch tube being too large to cause the switch tube to overheat, and even damage. While in the case where the current in the loop is small, the number of switch tubes turned on can be reduced.

[0116] In the above, which loop the first bridge arm 210 and the second bridge arm 220 belong to depends on which of the positive electrode and the negative electrode of the power battery pack is connected to the motor, that is, which of the first connection end and the second connection end in the battery pack interface 300 is connected to the motor M, which can be seen from the relevant description below. The following describes the process of alternately switching the step-down charging loop and the step-up charging loop by taking the first bridge arm 210 belonging to the step-up charging loop and the second bridge arm 220 belonging to the step-down charging loop as an example:

[0117] Firstly, the controller controls the first bridge arm 210 to be off and the second bridge arm 220 to be on, in this case, the current of the external DC power supply flows out from the positive access end of the charging interface 100, passes through the power battery pack, the first relay K1, the inductor and the second bridge arm 220, and then flows back to the negative pole of the external DC power supply through the negative access end of the charging interface 100, thereby forming a step-down charging loop for charging the power battery pack and the inductor. In this process, the step-down charging loop has a step-down effect on the external DC power supply, so as to reduce the voltage output by the external DC power supply to the charging voltage of the power battery pack, and the current of the external DC power supply is pulled to the maximum.

[0118] When the period of the alternating on-off control arrives, the controller controls the first bridge arm 210 to be on and the second bridge arm 220 to be off, in this case, the current of the inductor flows out from the first bridge arm 210 and then flows back to the inductor after passing through the power battery pack, thereby forming a step-up charging loop for charging the power battery pack. In this process, since the charging power of the external DC power supply remains unchanged, the overall charging power of the step-up charging loop also remains unchanged, and the power is equal to the product of voltage and current, so the decrease of the charging voltage can increase the charging current, thereby improving the charging speed.

[0119] Therefore, after the battery charging and discharging device is connected to the above-mentioned external DC power supply, the alternating on-off of the first bridge arm 210 and the second bridge arm 220 can realize that the external DC power supply intermittently charges the inductor and the power battery pack in a step-down manner, and then intermittently charges the power battery pack in a step-up manner through the inductor, until the power battery pack is fully charged or the external DC power supply is disconnected.

[0120] Although the controller is mentioned in the embodiments of the utility model, the related control scheme in the controller depends on the circuit composition of the battery charging and discharging device provided by the embodiments of the utility model, and the circuit composition is the protection focus of the embodiments of the utility model, and the related control scheme is not the protection focus, so it should not be understood that the embodiments of the utility model relate to method improvement.

[0121] From the above, which of the first access end and the second access end in the battery pack interface 300 is connected with the motor M will affect the circuit to which the first bridge arm 210 and the second bridge arm 220 belong, and further affect the on-off control sequence of the first bridge arm 210 and the second bridge arm 220.

[0122] For this, the embodiments of the utility model provide two connection schemes between the battery pack interface 300 and the motor M:

[0123] Firstly, the second access end of the battery pack interface 300 is connected with the motor M:

[0124] Please refer to Figure 2a and Figure 2b ,Figure 2a is a circuit principle diagram of a battery charging and discharging device provided by the embodiment of the utility model, Figure 2b is another circuit principle diagram of a battery charging and discharging device provided by the embodiment of the utility model, the connection mode of the second access end and the motor is different in the two drawings, Figure 2a the second access end in the drawing is connected with the neutral line of the motor M, and Figure 2b the second access end in the drawing is connected with one phase line of the motor M. But no matter which mode, the second access end (namely the negative pole of the power battery pack) is connected with the motor M.

[0125] In this case, the first bridge arm 210 belongs to the boost charging circuit, and the second bridge arm 220 belongs to the step-down charging circuit, that is, in the boost charging circuit, the first bridge arm 210 is in the conducting state, and the second bridge arm 220 is in the open state; and in the step-down charging circuit, the first bridge arm 210 is in the open state, and the second bridge arm 220 is in the conducting state. Taking the circuit shown in Figure 2a as an example, the current direction of the step-down charging circuit can be seen from the direction of the solid arrow in Figure 2a , and the current direction of the boost charging circuit can be seen from the direction of the dotted arrow in Figure 2a .

[0126] Secondly, the first access end of the battery pack interface 300 is connected with the motor M:

[0127] Please refer to Figure 3a and Figure 3b , Figure 3a is another circuit principle diagram of a battery charging and discharging device provided by the embodiment of the utility model, Figure 3b is another circuit principle diagram of a battery charging and discharging device provided by the embodiment of the utility model, the connection mode of the first access end and the motor is different in the two drawings, Figure 3a the first access end in the drawing is connected with the neutral line of the motor M, and Figure 3b the first access end in the drawing is connected with one phase line of the motor M. But no matter which mode, the first access end (namely the positive pole of the power battery pack) is connected with the motor M.

[0128] In this case, the first bridge arm 210 belongs to the step-down charging circuit, and the second bridge arm 220 belongs to the boost charging circuit, that is, in the step-down charging circuit, the first bridge arm 210 is in the conducting state, and the second bridge arm 220 is in the open state; and in the boost charging circuit, the first bridge arm 210 is in the open state, and the second bridge arm 220 is in the conducting state. Taking the circuit shown in Figure 3a as an example, the current direction of the step-down charging circuit can be seen from the direction of the solid arrow in Figure 3aThe direction indicated by the middle solid arrow: negative access end → power battery pack 2 → power battery pack 1 → inductance of motor M → first bridge arm 210 → positive access end → negative access end. The current direction of the boost charging circuit can be seen from the following figure. Figure 3a The direction indicated by the middle dashed arrow: inductance of motor M → second bridge arm 220 → power battery pack 2 → power battery pack 1 → inductance of motor M.

[0129] In the above, Figure 2a to Figure 3b In the circuit principle diagram shown, other devices except the charging interface 100, the electric drive assembly 200 and the power battery pack 300 can be omitted, because the layout of these other devices is designed to achieve other circuit functions, which belongs to other transformation schemes, and specific reference can be made to the relevant description in the following.

[0130] In addition, for the convenience of the following description, in the embodiment of the utility model, the charging mode in which the above-mentioned step-down charging circuit and the boost charging circuit are alternately switched is simply referred to as the step-down boost charging mode.

[0131] Since the external DC power supply can be a high-voltage high-current type power supply, the high-voltage high-current type can mean that the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack, and the output current of the external DC power supply is greater than or equal to the maximum charging current of the power battery pack. In this case, in order to better improve the charging speed of the power battery pack, the external DC power supply can be used to directly charge the power battery pack. Therefore, in some embodiments, the battery charging and discharging device provided by the embodiment of the utility model can also have a direct charging function, and accordingly can also include:

[0132] The first relay K1 is connected in series between the motor M and one end of the battery pack interface 300 connected with the motor M;

[0133] And the second relay K2 is connected in parallel with the branch formed by the first relay K1 and the electric drive assembly 200.

[0134] In the case where the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack, and the output current of the external DC power supply is greater than or equal to the maximum charging current of the power battery pack, the first relay K1, the first bridge arm 210 and the second bridge arm 220 are all in the off state, the second relay K2 is in the on state, and the external DC power supply, the power battery pack and the second relay K2 form a direct charging circuit.

[0135] Thus, in the case that the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack and the output current of the external DC power supply is greater than or equal to the maximum charging current of the power battery pack, the external DC power supply can directly charge the power battery pack, which is beneficial to improve the charging speed.

[0136] Correspondingly, in the case that the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack and the output current of the external DC power supply is less than the maximum charging current of the power battery pack, the second relay K2 is in an open state. It can be understood that, in the step-down step-up charging mode, the second relay K2 remains open to avoid short-circuiting the branch formed by the first relay K1 and the electric drive assembly 200, thereby affecting the normal operation of the step-down step-up charging mode.

[0137] It can be seen that the configuration of the first relay K1 and the second relay K2 can make the step-down step-up charging mode and the DC charging mode not affect each other, and can make the battery charging and discharging device compatible with more charging piles with different parameters.

[0138] In the above, the positions of the first relay K1 and the second relay K2 in the circuit also change with the connection mode of the battery pack interface and the motor M. For example, in the case that the second access end is connected with the motor M, please continue to refer to Figure 2a and Figure 2b , the first relay K1 is connected between the second access end and the motor M, and the second relay K2 is connected between the second access end and the second end of the second bridge arm 220. For another example, in the case that the first access end is connected with the motor M, please continue to refer to Figure 3a and Figure 3b , the first relay K1 is connected between the first access end and the motor M, and the second relay K2 is connected between the first access end and the second end of the first bridge arm 210.

[0139] However, in any of the above cases, the current flow direction in the DC charging circuit does not change, as shown by the arrow direction in Figure 2b .

[0140] In some embodiments, to improve the safety of the circuit, the battery charging and discharging device provided in the embodiments of the utility model can further include a third relay. The third relay is connected in series between the battery pack interface 300 and the electric drive assembly 200, and the third relay and the second relay K2 are connected to different access ends of the battery pack interface 300.

[0141] Similarly, the position of the third relay in the circuit changes with the position of the second relay K2 in the circuit. For example, in the case that the second relay K2 is connected between the second access end and the second end of the second bridge arm 220, please continue to refer toFigure 2a and Figure 2b The third relay K3 is connected between the first access end and the second end of the first bridge arm 210. Figure 3a and Figure 3b The third relay K3 is connected between the second access end and the second end of the second bridge arm 220.

[0142] As can be seen from the above, the third relay K3 can isolate one end of the battery pack interface 300 and the electric drive assembly 200 in the circuit, and also has the functions of the relay itself, including but not limited to: automatically disconnecting the circuit when the current or voltage in the circuit exceeds the limit value, thereby preventing equipment damage and effectively avoiding faults and losses caused by overloading or short circuit. In addition, the second relay K2, in addition to the function of enabling the direct charging circuit to conduct as described above, can also isolate the other end of the battery pack interface 300 and the electric drive assembly 200, and also has the functions of the relay itself.

[0143] Therefore, through the second relay K2 and the third relay K3, the safety and reliability of the circuit can be improved.

[0144] In some embodiments, to improve the safety of the circuit, please refer to Figure 2a The battery charging and discharging device provided in the embodiments of the present application can further include at least one of the following circuit safety configuration schemes:

[0145] Firstly, a relay is connected in series between the battery pack interface 300 and the first bridge arm 210;

[0146] Secondly, a relay is connected in series between the battery pack interface 300 and the second bridge arm 220;

[0147] Thirdly, a relay Ka is connected in series between the first bridge arm 210 and the positive access end;

[0148] Fourthly, a relay Kb is connected in series between the second bridge arm 220 and the negative access end;

[0149] Fifthly, a main fuse A is connected in series between the battery pack interface 300 and the first bridge arm 210;

[0150] Sixthly, a shunt B is connected in series between the battery pack interface 300 and the second bridge arm 220.

[0151] For the first and second circuit safety configuration schemes, in the embodiments of the battery charging and discharging device provided by the utility model, the relay connected in series between the battery pack interface 300 and the first bridge arm 210 can be one of the second relay K2 and the third relay K3, and the relay connected in series between the battery pack interface 300 and the second bridge arm 220 can be the other one of the second relay K2 and the third relay K3, so that the device multiplexing can be realized, and the circuit configuration cost can be reduced. Of course, the existing devices can not be multiplexed, but the corresponding relays can be additionally configured.

[0152] In addition, the roles and beneficial effects of the relays configured in the first and second circuit safety configuration schemes can be referred to the roles and beneficial effects of the second relay K2 and the third relay K3, which are described above, and will not be described here.

[0153] For the relays (Ka and Kb) configured in the third and fourth circuit safety configuration schemes, the circuit isolation and circuit safety technical effects described above can also be achieved. In addition, since the relay Ka and the relay Kb are disconnected in the uncharged state, the charging interface 100 will not be electrified after being disconnected from the external DC power supply, so that the safety of the user using the charging interface 100 can be ensured.

[0154] In addition to the two types of external DC power sources described above, the external DC power source can also be a low-voltage type, wherein the low-voltage type refers to that the output voltage of the external DC power source is lower than the charging voltage of the power battery pack. Therefore, in order to ensure that the charging demand of the power battery pack can still be met in this case, in some embodiments, the battery charging and discharging device provided by the utility model embodiments can also provide a boost charging function, that is, the battery charging and discharging device provided by the utility model embodiments can also include:

[0155] The first relay K1 is connected in series between the motor M and one end of the battery pack interface 300 connected to the motor M;

[0156] The fourth relay K4 is connected to the motor M at one end and connected to the target bridge arm at the other end, and the target bridge arm is the first bridge arm 210 or the second bridge arm 220;

[0157] And the fifth relay K5 is connected between the target bridge arm and the fourth relay K4.

[0158] It can be understood that the position of the fifth relay K5 in the circuit is determined by the connection mode of the fourth relay K4 in the circuit, which mainly includes two cases:

[0159] The first case: please refer toFigure 4a 、 Figure 4d 、 Figure 4e and Figure 4h , Figure 4a is a circuit schematic of a battery charging and discharging device with boost charging function provided by the embodiments of the present application, Figure 4d 、 Figure 4e and Figure 4h are circuit schematics of another battery charging and discharging device with boost charging function provided by the embodiments of the present application, in the examples shown in these diagrams, the target bridge arm connected by the fourth relay K4 is the second bridge arm 220, and it can be seen that the fourth relay K4 is also connected to the negative access end of the charging interface 100, in order to realize boost charging, the current output by the external DC power supply needs to be introduced into the inductance of the motor M through the fourth relay K4, therefore, the fifth relay K5 needs to be connected between the second bridge arm 220 and the fourth relay K4, so as to disconnect the fifth relay K5 in the boost charging mode, so as to prevent the current of the power battery pack from flowing out to the external DC power supply through the fifth relay K5 in the case that the terminal voltage of the external DC current and the inductance is less than the terminal voltage of the power battery pack, and also to avoid that part of the inductance in the motor M is short-circuited, wherein, Figure 4e and Figure 4h the relay K9 can be used as an isolation relay, which can be configured in the circuit or not.

[0160] For the above-mentioned first case, on the basis of the embodiment that the relay Kb is connected in series between the second bridge arm 220 and the negative access end in the battery charging and discharging device, the fifth relay K5 can reuse the relay Kb, or it can be said that the relay Kb reuses the fifth relay K5. That is to say, the fifth relay K5 not only can have the related functions of the relay Kb, but also can be applied in the boost charging mode to ensure the normal operation of the boost charging mode.

[0161] The second case: please refer to Figure 4b 、 Figure 4c 、 Figure 4f and Figure 4g, all are circuit principle diagrams of the battery charge-discharge device with the boost charging function provided by the embodiments of the present application, in the examples shown in these diagrams, the target bridge arm connected by the fourth relay K4 is the first bridge arm 210, it can be seen that the fourth relay K4 will also be connected to the positive access end of the charging interface 100, similarly, in order to realize boost charging, the current output by the external DC power supply needs to be introduced into the inductor of the motor M through the fourth relay K4, therefore, the fifth relay K5 needs to be connected between the first bridge arm 210 and the fourth relay K4, so as to disconnect the fifth relay K5 in the boost charging mode, so as to prevent the current of the power battery pack from flowing out to the external DC power supply through the fifth relay K5 in the case that the terminal voltage of the external DC current and the inductor is less than the terminal voltage of the power battery pack. Figure 4f and Figure 4g The relay K9 in the above-mentioned two cases can be used as an isolation relay, which can be configured in the circuit or not.

[0162] Similarly, for the above-mentioned second case, on the basis of the embodiment that the relay Ka is connected in series between the first bridge arm 210 and the positive access end in the battery charge-discharge device, the fifth relay K5 can reuse the relay Ka, or the relay Ka can reuse the fifth relay K5. That is to say, the fifth relay K5 not only can have the related functions of the relay Ka, but also can be applied to the boost charging mode to ensure the normal operation of the boost charging mode.

[0163] Figure 4a to Figure 4h In addition to showing the related circuit structures in the above-mentioned two cases, various connection modes of the first relay K1 and the fourth relay K4 in the circuit are also shown, that is to say, the circuit structure of the battery charge-discharge device with the boost charging function provided by the embodiments of the present application has various implementation modes.

[0164] In the case that the output voltage of the external DC power supply is lower than or equal to the charging voltage of the power battery pack, no matter which circuit implementation mode of the battery charge-discharge device with the boost charging function is used, the first relay K1 and the fifth relay K5 in the circuit are both in the off state, the fourth relay K4 is in the on state, and the first bridge arm 210 and the second bridge arm 220 are alternately turned on and off to alternately switch the energy storage charging loop and the boost charging loop.

[0165] The energy storage charging loop is used to charge the inductor, and the energy storage charging loop includes the external DC power supply, the fourth relay K4, the inductor, and the bridge arm in the on state in the energy storage charging loop.

[0166] In the case that the output voltage of the external DC power supply is lower than or equal to the charging voltage of the power battery pack, no matter which circuit implementation mode of the battery charge-discharge device with the boost charging function is used, the first relay K1 and the fifth relay K5 in the circuit are both in the off state, the fourth relay K4 is in the on state, and the first bridge arm 210 and the second bridge arm 220 are alternately turned on and off to alternately switch the energy storage charging loop and the boost charging loop. Figure 4cFor example, the current flow in the energy storage charging circuit is as follows: the current from the external DC power supply flows out through the positive terminal of the charging interface 100, and sequentially passes through the fourth relay K4, the inductance of the motor M, and the second bridge arm 220, and then flows back to the negative terminal of the external DC power supply from the negative terminal of the charging interface 100. Figure 4c As shown by the solid arrow in the diagram, this forms an energy storage and charging circuit. It can be seen that in this situation, the fifth relay K5, the first bridge arm 210, and the first relay K1 are all in the open state.

[0167] The boost charging circuit is used to charge the power battery pack. The boost charging circuit includes the external DC power supply, the fourth relay K4, the inductor, the bridge arm that is in the conducting state in the boost charging circuit, and the power battery pack.

[0168] by Figure 4c For example, the current flow in the boost charging circuit is as follows: the current from the external DC power supply flows out through the positive terminal of the charging interface 100, and sequentially passes through the fourth relay K4, the inductor of the motor M, the first bridge arm 210, the power battery pack, and the second relay K2, and then flows back to the negative terminal of the external DC power supply from the negative terminal of the charging interface 100. Figure 4c As indicated by the dashed arrow, this forms a boost charging circuit. It can be seen that in this configuration, the external DC power supply and the inductor already charged by the boost charging circuit are connected in series, equivalent to two power supplies connected in series. This effectively increases the voltage of the power supply used to charge the battery pack, thus enabling the charging needs of the battery pack to be met even when the output voltage of the external DC power supply is lower than the charging voltage of the battery pack. In the boost charging circuit, the first relay K1 and the fifth relay K5 remain open, the second bridge arm 220 switches from the on state to the off state, and the first bridge arm 210 switches from the off state to the on state.

[0169] The configuration of the alternating control frequency of the first bridge arm 210 and the second bridge arm 220 mentioned above can be found in the relevant description above. It can be the same as the frequency used above, or it can be different.

[0170] In buck-boost charging mode, a large ripple current may exist in the boost charging circuit. This ripple current can affect battery lifespan and cause battery temperature rise, which in turn affects battery performance. Therefore, to avoid the adverse effects of ripple current on battery lifespan and performance, in some embodiments, please refer to... Figure 5a , Figure 5a This is a circuit diagram of a battery charging and discharging device with a first voltage-stabilizing capacitor provided in an embodiment of the present invention. The battery charging and discharging device provided in this embodiment of the present invention may further include a first voltage-stabilizing capacitor C1, which is connected in parallel with the battery pack interface 300.

[0171] From Figure 5a It can be seen that the first voltage stabilizing capacitor C1 is connected in parallel across the battery pack interface 300. It can be seen that the first voltage stabilizing capacitor C1 and the battery pack interface 300 are in communication, so that, on the one hand, at the moment when the power battery pack is powered on, the first voltage stabilizing capacitor C1 may have a sparking phenomenon, thereby causing a risk of burning the circuit; on the other hand, due to the presence of the power battery pack, the first voltage stabilizing capacitor C1 will be charged, and then during the assembly of the first voltage stabilizing capacitor C1, the assembler or the assembled device may be electrically shocked due to the discharge of the first voltage stabilizing capacitor C1, thereby there is a certain assembly risk. Therefore, in order to avoid the sparking phenomenon of the first voltage stabilizing capacitor C1 and reduce the assembly risk of the first voltage stabilizing capacitor C1, in some embodiments, the battery charging and discharging device provided by the embodiment of the utility model can also be configured with corresponding safety protection devices for the first voltage stabilizing capacitor C1, that is, at least one of the two ends of the first voltage stabilizing capacitor C1 is connected with the battery pack interface 300 through a relay. Thus, in the case that the battery charging and discharging device is not in a working state, the relay between the first voltage stabilizing capacitor C1 and the battery pack interface 300 can be disconnected, so that the first voltage stabilizing capacitor C1 is not charged, the assembly risk can be reduced, and the sparking phenomenon can also be avoided.

[0172] For the above-mentioned scheme of configuring a relay between the first voltage stabilizing capacitor C1 and the battery pack interface 300, the embodiment of the utility model also provides a plurality of implementation manners, please refer to Figure 5b to Figure 5k , Figure 5b to Figure 5k are another kind of circuit principle diagram of the battery charging and discharging device provided by the embodiment of the utility model with the first voltage stabilizing capacitor. From Figure 5b It can be seen that one end of the first voltage stabilizing capacitor C1 is connected with the first access end through the third relay K3, thereby the isolation between the first voltage stabilizing capacitor C1 and the positive electrode of the power battery pack can be realized, and the sparking risk and the assembly risk can be reduced.

[0173] And Figure 5c to Figure 5k In each circuit principle diagram shown in the drawings, although there are a plurality of transformation modes for the connection mode of the first voltage stabilizing capacitor C1 and part of the devices in the circuit, no matter which transformation mode, the two ends of the first voltage stabilizing capacitor C1 are connected with the first access end and the second access end of the battery pack interface 300 through the third relay K3 and the eighth relay K8 respectively, thereby the isolation between the two ends of the first voltage stabilizing capacitor C1 and the power battery pack can be realized, and the sparking risk and the assembly risk can be better reduced. Figure 5h 、 Figure 5i 、 Figure 5j and Figure 5k In the drawings, the relay K9 plays an isolation role.

[0174] Since the battery temperature will decrease to some extent in a low-temperature environment, thereby affecting the battery performance, for example, affecting the power supply performance and charging speed of the battery, in order to ensure the performance of the power battery pack in a low-temperature environment, in some embodiments, the battery charging and discharging device provided by the embodiment of the utility model can also have a battery preheating function, that is, the battery charging and discharging device provided by the embodiment of the utility model can also include a sixth relay, one end of the sixth relay is connected between a plurality of battery groups contained in the power battery pack, and the other end is connected to the motor M, such as Figure 6a or Figure 6b as shown, Figure 6a and Figure 6b are a circuit principle diagram of a battery charging and discharging device provided by the embodiment of the utility model with a battery preheating function, which presents two circuit connection modes of the sixth relay, but is not limited thereto, for example, although Figure 6a and Figure 6b in the circuit, one end of the sixth relay K6 is connected to the voltage midpoint of the plurality of battery groups contained in the power battery pack, for example, assuming that the power battery pack includes power battery group 1 and power battery group 2, and the voltages of the power battery group 1 and the power battery group 2 are the same, then the voltage midpoint at this time represents the midpoint of the connection line between the power battery group 1 and the power battery group 2. Connecting one end of the sixth relay K6 to the voltage midpoint can ensure that the battery charging and discharging is balanced during the subsequent battery preheating process. However, in other variant embodiments, one end of the sixth relay K6 can also be connected to a certain point in the power battery group 1 or a certain point in the power battery group 2, as long as the battery preheating can be achieved, and it is not necessarily connected to the voltage midpoint.

[0175] Therefore, the battery temperature can be detected by the temperature sensor arranged at the power battery pack and fed back to the controller, the controller can compare the battery temperature with the set temperature threshold according to the relevant technical principle, and control the on-off of the corresponding relay according to the comparison result:

[0176] In the case where the temperature of the power battery pack is less than the set temperature threshold, the first relay K1 is in an open state, the sixth relay K6 is in a conductive state, the second relay K2 and the third relay K3 are alternately turned on and off, and the first bridge arm 210 and the second bridge arm 220 are alternately turned on and off, so as to alternately switch the battery discharging circuit and the battery charging circuit, and to realize the temperature rise of the power battery pack.

[0177] In the battery discharging circuit, the third relay K3 is turned on, the second relay K2 is turned off, part of the battery groups in the power battery pack are short-circuited by the sixth relay K6, and the battery groups in the power battery pack which are not short-circuited discharge to the inductor.

[0178] In the battery charging circuit, the second relay K2 is turned on, the third relay K3 is turned off, part of the battery groups in the power battery pack are short-circuited by the sixth relay K6, and the battery groups in the power battery pack which are not short-circuited charge from the inductor. Figure 6aAs shown, the current flow direction of the battery discharge circuit is: the current flows out from the positive electrode of the power battery pack 1, sequentially passes through the third relay K3, the first bridge arm 210, the inductor of the motor M and the sixth relay K6, and then flows back to the negative electrode of the power battery pack 1, thereby forming the battery discharge circuit, and realizing the discharge of the power battery pack 1 that is not short-circuited to the inductor, i.e., the inductor is in a charging state.

[0179] In this case, the first relay K1, the second relay K2 and the second bridge arm 220 are all in the open state.

[0180] In the battery discharge circuit, the second relay K2 is turned on, the third relay K3 is turned off, part of the battery packs in the power battery pack are in an open circuit, and the battery packs in the power battery pack that are not in the open circuit are charged by the inductor.

[0181] In this way, Figure 6a As shown, the current flow direction of the battery discharge circuit is: the current flows out from the positive electrode of the power battery pack 1, sequentially passes through the third relay K3, the first bridge arm 210, the inductor of the motor M and the sixth relay K6, and then flows back to the negative electrode of the power battery pack 1, thereby forming the battery discharge circuit, and realizing the discharge of the power battery pack 1 that is not short-circuited to the inductor, i.e., the inductor is in a charging state.

[0182] In this case, the first relay K1, the second relay K2 and the second bridge arm 220 are all in the open state.

[0183] In this way, by controlling the battery discharge circuit to operate first, and then controlling the battery charging circuit to operate, and alternately enabling the battery discharge circuit and the battery charging circuit according to this strategy, the heat generated by the alternating discharge and charging of the power battery pack can be used to improve the battery temperature of the power battery pack. When the battery temperature reaches the set temperature threshold, the battery preheating function can be stopped.

[0184] The alternating control frequency of the battery charging circuit and the battery discharge circuit can also be referred to the relevant description above, and will not be described here.

[0185] In some embodiments, to improve the practicability of the battery charging and discharging device, the battery charging and discharging device can also be used to charge an external load, i.e., the charging interface 100 can be used to connect an external load in addition to connecting an external DC power supply, to supply power to the external load.

[0186] In some embodiments, to improve the practicability of the battery charging and discharging device, the battery charging and discharging device provided in the embodiment of the utility model can also charge the electric equipment, wherein the electric equipment can be the electric equipment contained in the carrier powered by the battery charging and discharging device, and the electric equipment can also be referred to as an internal load, and the internal load can be a high-voltage internal load. Based on this, the battery charging and discharging device provided in the embodiment of the utility model can also include

[0187] The electric equipment assembly includes an electric equipment interface and a power supply interface.

[0188] The electric equipment interface is used for accessing the electric equipment.

[0189] The power supply interface is connected with the charging interface 100 or the battery pack interface 300, and is used for introducing an external direct-current power supply through the charging interface 100 or introducing a power supply provided by the power battery pack through the battery pack interface 300 to charge and discharge the battery charging and discharging device.

[0190] For the application scenario that the battery charging and discharging device accesses the high-voltage load, the embodiment of the utility model provides various implementation manners of the battery charging and discharging device accessing the high-voltage load, please refer to Figure 7a to Figure 7e , Figure 7a to Figure 7e Both are the circuit principle diagram of the battery charging and discharging device accessing the internal load provided in the embodiment of the utility model, and various different transformation modes are presented, which are mainly divided into two categories in essence.

[0191] The first category: the internal load draws power from the external direct-current power supply, as shown in Figure 7a and Figure 7b .

[0192] The second category: the internal load draws power from the power battery pack, as shown in Figure 7c to Figure 7e .

[0193] In the above, the internal load drawing power from the power battery pack has better stability and safety, because the withstand voltage of the internal load is generally matched with the voltage of the power battery pack in the production stage, and the types of the external direct-current power supply are various, and the output voltage of the external direct-current power supply may not be matched with the voltage of the internal load. Therefore, the voltage of the power battery pack will not be too high compared with the withstand voltage of the internal load, and thus the internal load can be prevented from being burned out due to the too high supply voltage of the internal load.

[0194] In the driving working condition, that is, in the case that the power battery pack supplies power to the electric drive assembly 200, to avoid that a large instantaneous voltage is generated in the circuit in the moment when the path between the power battery pack and the electric drive assembly 200 is conducted, and an impact on the motor M of the electric drive assembly 200 is caused, and thus the performance or service life of the motor M is affected, in some embodiments, please refer to Figure 2aThe electric drive assembly 200 may also include a second voltage regulator capacitor C2, which is connected between the first bridge arm 210 and the second bridge arm 220.

[0195] Therefore, by using the second voltage regulator capacitor C2, the voltage can be regulated at the moment the circuit between the power battery pack and the electric drive assembly 200 is turned on. Then, after the voltage stabilizes, the electric drive assembly 200 is powered, which can avoid the impact of large instantaneous voltage on the motor M.

[0196] Based on the previous embodiment, in order to avoid large instantaneous voltage breakdown of the second voltage regulator C2 under driving conditions, in some embodiments, the battery charging and discharging device provided by this utility model further includes a pre-charging circuit, so that the second voltage regulator C2 is charged first under driving conditions, so that the terminal voltage of the second voltage regulator C2 and the voltage of the power battery pack are maintained within a set voltage difference, thereby effectively preventing instantaneous voltage breakdown of the second voltage regulator C2.

[0197] Accordingly, the battery charging and discharging device provided in this embodiment of the present invention may further include:

[0198] The pre-charging circuit includes a resistor and a seventh relay connected in series; the pre-charging circuit is connected in parallel with the relay connected to the first access terminal;

[0199] When the difference between the terminal voltage of the second voltage stabilizing capacitor C2 and the terminal voltage of the power battery pack is greater than or equal to a set voltage difference, the seventh relay is in the conducting state, and the relay connected in parallel with the pre-charging circuit is in the disconnected state.

[0200] When the difference between the terminal voltage of the second voltage stabilizing capacitor C2 and the terminal voltage of the power battery pack is less than a set voltage difference value, the seventh relay is in the open state, and the relay connected in parallel with the pre-charging circuit is in the on state.

[0201] by Figure 2a For example, in this example, the relay connected to the first access terminal is the third relay K3. Therefore, the pre-charging circuit is connected in parallel with the third relay K3. Thus, under driving conditions, the second relay K2 can be turned on first, and then the seventh relay K7 can be turned on. At this time, the current of the power battery pack flows through the resistor R, the seventh relay K7, the second voltage regulator capacitor C2 and the second relay K2 in sequence, and then flows back to the negative terminal of the power battery pack. This achieves pre-charging of the second voltage regulator capacitor C2 and avoids instantaneous voltage breakdown of the second voltage regulator capacitor C2.

[0202] In the process of pre-charging the second voltage stabilizing capacitor C2, the terminal voltage of the second voltage stabilizing capacitor C2 and the terminal voltage of the power battery pack can be obtained through a related technical principle, so that the seventh relay K7 is controlled to be turned off and the third relay K3 is controlled to be turned on when the difference between the terminal voltages of the two is less than the set voltage difference, thereby realizing that the terminal voltage of the electric drive system assembly is stabilized, and then the power battery pack supplies power to the electric drive system assembly.

[0203] In the above, the set voltage difference can be set according to experiments or experience, for example, 5V, but is not limited thereto.

[0204] Based on the embodiment of the battery charging and discharging device with the pre-charging function and the first voltage stabilizing capacitor C1, in addition to the circuit connection mode shown in the above, the first voltage stabilizing capacitor C1 can also have another variant connection mode, as shown in the above, Figure 5a to Figure 5g Figure 8 Figure 8 is a circuit principle diagram of another battery charging and discharging device provided by the embodiment of the utility model, one end of the first voltage stabilizing capacitor C1 connected with the first access end can be transferred and connected between the resistor R and the seventh relay K7.

[0205] Corresponding to the embodiment of the battery charging and discharging device, the embodiment of the utility model further provides a new energy automobile, which comprises:

[0206] a power battery pack; and

[0207] a battery charging and discharging device; the battery charging and discharging device is the battery charging and discharging device in any of the above embodiments.

[0208] In the above, the charging and discharging principle and the driving principle of the new energy automobile can be referred to the description of the corresponding embodiment of the battery charging and discharging device provided by the utility model, and will not be repeated here.

[0209] It is worth noting that the technical features or technical solutions in any of the above embodiments of the utility model can be combined or combined, as long as there is no contradiction in combination or combination.

[0210] The above only describes the preferred embodiments of the utility model, and is not used to limit the utility model. For those skilled in the art, the utility model can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.​​

Claims

1. A battery charging and discharging device, characterized in that, include: The charging interface is used to connect to an external DC power source, and includes a positive input terminal and a negative input terminal. An electric drive assembly includes a motor, a first bridge arm, and a second bridge arm; each phase line of the motor is connected to a first end of the first bridge arm and a first end of the second bridge arm, respectively; the second end of the first bridge arm is connected to the positive terminal; and the second end of the second bridge arm is connected to the negative terminal. A battery pack interface, wherein a first access terminal for connecting to the positive terminal of the power battery pack is connected to the second end of the first bridge arm, and a second access terminal for connecting to the negative terminal of the power battery pack is connected to the second end of the second bridge arm, and one of the first access terminal and the second access terminal is connected to the motor; When the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack and the output current of the external DC power supply is less than the maximum charging current of the power battery pack, the first bridge arm and the second bridge arm are alternately switched on and off to alternately switch between the buck charging circuit and the boost charging circuit. The buck charging circuit is used to charge the inductor in the motor and the power battery pack. The buck charging circuit includes the external DC power supply, the power battery pack, a bridge arm that is in a conducting state in the buck charging circuit, and the inductor. The boost charging circuit is used to charge the power battery pack. The boost charging circuit includes the power battery pack, a bridge arm that is in a conducting state in the boost charging circuit, and the inductor.

2. The apparatus according to claim 1, characterized in that, The second access terminal is connected to the motor; In the step-down charging circuit, the first bridge arm is in the open state and the second bridge arm is in the on state; In the current boosting charging circuit, the first bridge arm is in the on state, and the second bridge arm is in the off state.

3. The apparatus according to claim 1, characterized in that, The first access terminal is connected to the motor; In the step-down charging circuit, the first bridge arm is in the on state and the second bridge arm is in the off state; In the current boost charging circuit, the first bridge arm is in the off state and the second bridge arm is in the on state.

4. The apparatus according to claim 1, characterized in that, Also includes: The first relay is connected in series between the motor and the end of the battery pack interface that is connected to the motor; And a second relay, which is connected in parallel with the branch formed by the first relay and the electric drive assembly; When the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack, and the output current of the external DC power supply is greater than or equal to the maximum charging current of the power battery pack, the first relay, the first bridge arm, and the second bridge arm are all in the open state, the second relay is in the closed state, and the external DC power supply, the power battery pack, and the second relay form a direct charging circuit. When the output voltage of the external DC power supply is higher than the charging voltage of the power battery pack and the output current of the external DC power supply is less than the maximum charging current of the power battery pack, the second relay is in the open state.

5. The apparatus according to claim 4, characterized in that, It also includes a third relay; the third relay is connected in series between the battery pack interface and the electric drive assembly, and the third relay and the second relay are connected to different access terminals of the battery pack interface.

6. The apparatus according to claim 1, characterized in that, Also includes: The first relay is connected in series between the motor and the end of the battery pack interface that is connected to the motor; The fourth relay has one end connected to the motor and the other end connected to the target bridge arm, which is either the first bridge arm or the second bridge arm; And a fifth relay, connected between the target bridge arm and the fourth relay; When the output voltage of the external DC power supply is lower than or equal to the charging voltage of the power battery pack, the first relay and the fifth relay are in the off state, the fourth relay is in the on state, and the first bridge arm and the second bridge arm are alternately switched on and off to alternately switch the energy storage charging circuit and the boost charging circuit. The energy storage charging circuit is used to charge the inductor. The energy storage charging circuit includes the external DC power supply, the fourth relay, the inductor, and a bridge arm that is in a conducting state in the energy storage charging circuit. The boost charging circuit is used to charge the power battery pack. The boost charging circuit includes the external DC power supply, the fourth relay, the inductor, the bridge arm that is in the conducting state in the boost charging circuit, and the power battery pack.

7. The apparatus according to claim 1, characterized in that, It also includes a first voltage-regulating capacitor; the first voltage-regulating capacitor is connected in parallel with the battery pack interface.

8. The apparatus according to claim 7, characterized in that, At least one of the two ends of the first voltage-stabilizing capacitor is connected to the battery pack interface via a relay.

9. The apparatus according to claim 1, characterized in that, A relay is connected in series between the battery pack interface and the first bridge arm; and / or A relay is connected in series between the battery pack interface and the second bridge arm; and / or A relay is connected in series between the first bridge arm and the positive terminal; and / or A relay is connected in series between the second bridge arm and the negative terminal; and / or A main fuse is connected in series between the battery pack interface and the first bridge arm; and / or A shunt is connected in series between the battery pack interface and the second bridge arm.

10. The apparatus according to claim 5, characterized in that, Also includes: The sixth relay has one end connected to the multiple battery packs contained in the power battery pack, and the other end connected to the motor; When the temperature of the power battery pack is lower than a set temperature threshold, the first relay is in the off state, the sixth relay is in the on state, the second relay and the third relay alternately turn on and off, and the first bridge arm and the second bridge arm alternately turn on and off, so as to alternately switch the battery discharge circuit and the battery charging circuit to heat up the power battery pack. In the battery discharge circuit, the third relay is turned on, the second relay is turned off, some battery packs in the power battery pack are short-circuited by the sixth relay, and the battery packs in the power battery pack that are not short-circuited discharge to the inductor. In the battery charging circuit, the second relay is turned on, the third relay is turned off, some battery packs in the power battery pack are in an open circuit, and the battery packs that are not in an open circuit are charged by the inductor.

11. The apparatus according to claim 1, characterized in that, The charging interface is also used to connect to an external load.

12. The apparatus according to claim 1, characterized in that, Also includes: Electrical equipment components, including electrical equipment interfaces and power interfaces; The electrical equipment interface is used to connect electrical equipment; The power interface is connected to the charging interface or the battery pack interface, and is used to introduce external DC power through the charging interface, or to introduce the power charging and discharging device provided by the power battery pack through the battery pack interface.

13. The apparatus according to claim 5, characterized in that, The electric drive assembly also includes a second voltage regulator capacitor, the two ends of which are respectively connected to the second end of the first bridge arm and the second end of the second bridge arm.

14. The apparatus according to claim 13, characterized in that, Also includes: The pre-charging circuit includes a resistor and a seventh relay connected in series; the pre-charging circuit is connected in parallel with the relay connected to the first access terminal; When the difference between the terminal voltage of the second voltage regulator and the terminal voltage of the power battery pack is greater than or equal to a set voltage difference, the seventh relay is in the on state, and the relay connected in parallel with the pre-charging circuit is in the off state. When the difference between the terminal voltage of the second voltage regulator and the terminal voltage of the power battery pack is less than a set voltage difference, the seventh relay is in the open state, and the relay connected in parallel with the pre-charging circuit is in the on state.

15. A new energy vehicle, characterized in that, include: Power battery pack; as well as A battery charging and discharging device; the battery charging and discharging device is the battery charging and discharging device according to any one of claims 1 to 14.

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